Tissue plasminogen activator and its receptor in the human amnion, chorion, and decidua at preterm and term

Genetics, epigenetics, and transcriptomics of preterm birth

Preterm birth contributes significantly to neonatal mortality and morbidity. Despite its global significance, there has only been limited progress in preventing preterm birth. Spontaneous preterm birth (sPTB) results from a wide variety of pathological processes. Although many non-genetic risk factors influence the timing of gestation and labor, compelling evidence supports the role of substantial genetic and epigenetic influences and their interactions with the environment contributing to sPTB. To investigate a common and complex disease such as sPTB, various approaches such as genome-wide association studies, whole-exome sequencing, transcriptomics, and integrative approaches combining these with other 'omics studies have been used. However, many of these studies were typically small or focused on a single ethnicity or geographic region with limited data, particularly in populations at high risk for sPTB, or lacked a robust replication. These studies found many genes involved in the inflammation and immunity-related pathways that may affect sPTB. Recent studies also suggest the role of epigenetic modifications of gene expression by the environmental signals as a potential contributor to the risk of sPTB. Future genetic studies of sPTB should continue to consider the contributions of both maternal and fetal genomes as well as their interaction with the environment.

Hemostasis System and Plasminogen Activity in Retrochorial Hematoma in the First Trimester of Pregnancy

(1) Background: The components of the fibrinolytic system and its main component, plasminogen, play a key role in the first months of pregnancy. The effect of autoantibodies interacting with plasminogen in the formation of retrochorial hematoma is unknown. The aim of our study was to determine the role of plasminogen and IgA, IgM, and IgG, which bind to plasminogen, in retrochorial hematoma. (2) Methods: Prothrombin time (PT), thrombin time (TT), partial activated thromboplastin time (aPTT), soluble fibrin-monomer complex (SFMC), D-dimer, plasminogen activity (%Plg), plasminogen concentration (Plg), and the levels of IgG (IgG-Plg), IgM (IgM-Plg), IgA (IgA-Plg) interacting with plasminogen were determined in plasma samples of 57 women with normal pregnancy and 16 with retrochorial hematoma. (3) Results: %Plg in plasma samples from women with retrochorial hematoma was significantly lower than in plasma samples from women with normal pregnancy. The diagnostic significance of %Plg in the ROC analysis was AUC = 0.85. A direct correlation was found between aPTT and the level of autologous IgM interacting with plasminogen. (4) Conclusions: A decrease in the activity of plasminogen in the blood serum of women in the first trimester of pregnancy may indicate disturbances in the hemostasis system and the formation of retrochorial hematoma. According to the results of the study, it is possible to recommend the determination of plasminogen activity in the management of pregnant women in gynecological practice.

Regulation of Placental Extravillous Trophoblasts by the Maternal Uterine Environment

During placentation invasive extravillous trophoblasts (EVTs) migrate into the maternal uterus and modify its vessels. In particular, remodeling of the spiral arteries by EVTs is critical for adapting blood flow and nutrient transport to the developing fetus. Failures in this process have been noticed in different pregnancy complications such as preeclampsia, intrauterine growth restriction, stillbirth, or recurrent abortion. Upon invasion into the decidua, the endometrium of pregnancy, EVTs encounter different maternal cell types such as decidual macrophages, uterine NK (uNK) cells and stromal cells expressing a plethora of growth factors and cytokines. Here, we will summarize development of the EVT lineage, a process occurring independently of the uterine environment, and formation of its different subtypes. Further, we will discuss interactions of EVTs with arteries, veins and lymphatics and illustrate how the decidua and its different immune cells regulate EVT differentiation, invasion and survival. The present literature suggests that the decidual environment and its soluble factors critically modulate EVT function and reproductive success.

Assessment of the cellular localisation of the annexin A2/S100A10 complex in human placenta

The AnxA2/S100A10 complex has been implicated in various placental functions but although the localisation of these proteins individually has been studied, there is no information about the localisation of their complex in situ at the cellular level. Using the proximity ligation technique, we have investigated the in situ localisation of AnxA2/S100A10 complex in the placenta and have compared this with the location patterns of the individual proteins. High levels of expression of AnxA2/S100A10 complexes were observed in the amniotic membrane and in blood vessel endothelial cells. Lower levels were detected in the brush border area of the syncytium and in the trophoblasts. Immunohistochemical analysis of AnxA2 and S100A10 individually revealed broadly similar patterns of localisation. The brush border staining pattern suggests that in this location at least some of the AnxA2 is not in complex with S100A10. The formal location of the AnxA2/S100A10 complex is compatible with a role in cell-cell interaction, intracellular transport and secretory processes and regulation of cell surface proteases, implying contributions to membrane integrity, nutrient exchange, placentation and vascular remodelling in different parts of the placenta. Future applications will allow specific assessment of the association of the complex with pathophysiological disorders.

Immune cell and transcriptomic analysis of the human decidua in term and preterm parturition

STUDY QUESTION

Is labour, both at term and preterm, associated with alterations in decidual lymphocyte densities and widespread changes to the decidual transcriptome?

SUMMARY ANSWER

The onset of parturition, both at term and preterm, is associated with widespread gene expression changes in the decidua, many of which are related to inflammatory signalling, but is not associated with changes in the number of any of the decidual lymphocyte populations examined.

WHAT IS KNOWN ALREADY

Given its location, directly at the maternal–foetal interface, the decidua is likely to play a pivotal role in the onset of parturition, however, the molecular events occurring in the decidua in association with the onset of labour, both at term and preterm, remain relatively poorly defined. Using flow cytometry and microarray analysis, the present study aimed to investigate changes to the immune cell milieu of the decidua in association with the onset of parturition and define the decidual gene signature associated with term and preterm labour (PTL).

STUDY DESIGN, SIZE, DURATION

This study used decidual samples collected from 36 women across four clinical groups: term (38–42 weeks of gestation) not in labour, TNL; term in labour, TL; preterm (<35 weeks of gestation)not in labour, PTNL; and preterm in labour, PTL.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Decidual lymphocytes were isolated from fresh decidual tissue collected from women in each of our four patient groups and stained with a panel of antibodies (CD45, CD3, CD19, CD56, CD4, CD8 and TCRVα24-Jα18) to investigate lymphocyte populations present in the decidua (TNL, n = 8; TL, n = 7; PTNL, n = 5; PTL, n = 5). RNA was extracted from decidual tissue and subjected to Illumina HT-12v4.0 BeadChip expression microarrays (TNL, n = 11; TL, n = 8; PTNL, n = 7; PTL, n = 10). Quantitative real-time PCR (qRT-PCR) was used to validate the microarray results.

MAIN RESULTS AND THE ROLE OF CHANCE

The relative proportions of decidual lymphocytes (T cells, NK cells, B cells and invariant natural killer (iNKT) cells) were unaffected by either gestation or labour status. However, we found elevated expression of the non-classical MHC-protein, CD1D, in PTL decidua samples (P < 0.05), suggesting the potential for increased activation of decidual invariant NKT (iNKT) cells in PTL. Both term and PTL were associated with widespread gene expression changes, particularly related to inflammatory signalling. Up-regulation of candidate genes in TL (IL-6, PTGS2, ATF3, IER3 and TNFAIP3) and PTL (CXCL8, MARCO, LILRA3 and PLAU) were confirmed by qRT-PCR analysis.

LARGE SCALE DATA

Microarray data are available at www.ebi.ac.uk/arrayexpress under accession number E-MTAB-5353.

LIMITATIONS REASONS FOR CAUTION

Whilst no changes in lymphocyte number were observed across our patient samples, we did not investigate the activation state of any of the immune cell sub-populations examined, therefore, it is possible that the function of these cells may be altered in association with labour onset. Additionally, the results of our transcriptomic analyses are descriptive and at this stage, we cannot prove direct causal link with the up-regulation of any of the genes examined and the onset of either term or PTL.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that the onset of parturition is associated with widespread changes to the decidual transcriptome, and there are distinct gene expression changes associated with term and PTL. We confirmed that an inflammatory signature is present within the decidua, and we also report the up-regulation of several genes involved in regulating the inflammatory response. The identification of genes involved in regulating the inflammatory response may provide novel molecular targets for the development of new, more effective therapies for the prevention of preterm birth (PTB). Such targets are urgently required.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by Medical Research Council (grant number MR/L002657/1) and Tommy's, the baby charity. Jane Norman has had research grants from the charity Tommy's and from the National Institute for Health Research on PTB during the lifetime of this project. Jane Norman also sits on a data monitoring committee for GSK for a study on PTB prevention and her institution receives financial recompense for this. The other authors do not have any conflicts of interest to declare.

11β-HSD1 in Human Fetal Membranes as a Potential Therapeutic Target for Preterm Birth

Human parturition is a complex process involving interactions between the myometrium and signals derived from the placenta, fetal membranes, and fetus. Signals originating from fetal membranes are crucial components that trigger parturition, which is clearly illustrated by the labor-initiating consequence of membrane rupture. It has been recognized for a long time that among fetal tissues in late gestation the fetal membranes possess the highest capacity for cortisol regeneration by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). However, the exact role of this unique feature remains a mystery. Accumulating evidence indicates that this extra-adrenal source of cortisol may serve as an upstream signal for critical events in human parturition, including enhanced prostaglandin and estrogen synthesis as well as extracellular matrix remodeling. This may explain why such high capacity for cortisol regeneration develops in human fetal membranes at late gestation. Therefore, inhibition of 11β-HSD1 may provide a potential therapeutic target for prevention of preterm birth. This review summarizes the current understanding of the functional role of cortisol regeneration by 11β-HSD1 in human fetal membranes.

The Role of Matrix Degrading Enzymes and Apoptosis in Repture of Membranes

Prematurity is the third leading cause of perinatal death, and preterm premature rupture of the membranes (pPROM) is associated with approximately 20-50% of all preterm births. The etiologic factors described for pPROM and preterm labor (PTL) are the same, although the clinical presentation (pPROM vs PTL) differs among patients. The reason for this disparity is unknown and poses a therapeutic dilemma. Several etiologic factors have been described for PTL and pPROM. PTL and pPROM are associated with overwhelming host inflammatory response. Many of these pro-inflammatory factors (inflammatory cytokine release) are common in both conditions; however, the clinical presentation differs. The objective of this review is to explain the differential expression pattern of matrix metalloproteinases (MMPs) and pro-apoptotic elements in human fetal membranes in pPROM and PTL and how they interact to present different clinical outcomes during pregnancy.

Localization of a major susceptibility locus influencing preterm birth

Preterm birth (PTB) is a complex trait, but little is known regarding its major genetic determinants. The objective of this study is to localize genes that influence susceptibility to PTB in Mexican Americans (MAs), a minority population in the USA, using predominantly microfilmed birth certificate-based data obtained from the San Antonio Family Birth Weight Study. Only 1302 singleton births from 288 families with information on PTB and significant covariates were considered for genetic analysis. PTB is defined as a childbirth that occurs at <37 completed weeks of gestation, and the prevalence of PTB in this sample was 6.4%. An ∼10 cM genetic map was used to conduct a genome-wide linkage analysis using the program SOLAR. The heritability of PTB was high (h(2) ± SE: 0.75 ± 0.20) and significant (P = 4.5 × 10(-5)), after adjusting for the significant effects of birthweight and birth order. We found significant evidence for linkage of PTB (LOD = 3.6; nominal P = 2.3 × 10(-5); empirical P = 1.0 × 10(-5)) on chromosome 18q between markers D18S1364 and D18S541. Several other chromosomal regions (2q, 9p, 16q and 20q) were also potentially linked with PTB. A strong positional candidate gene in the 18q linked region is SERPINB2 or PAI-2, a member of the plasminogen activator system that is associated with various reproductive processes. In conclusion, to our knowledge, perhaps for the first time in MAs or US populations, we have localized a major susceptibility locus for PTB on chromosome 18q21.33-q23.

Pathophysiology of the antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) are associated with the recurrent pregnancy loss and thrombosis that characterizes the antiphospholipid antibody syndrome (APS). Although the ontogeny of these pathogenic antibodies has not been fully elucidated, there is evidence that indicates the involvement of both genetic and environmental factors. The ability of aPL to induce a procoagulant phenotype in APS patients plays a central role in the development of arterial and venous thrombotic manifestations typical of the disease. Inflammation serves as a necessary link between this procoagulant phenotype and actual thrombus development and is an important mediator of the placental injury seen in APS patients with obstetric complications. Recent evidence has indicated a role for abnormal cellular proliferation and differentiation in the pathophysiology of APS, especially in those patients with pregnancy morbidity and other more atypical manifestations that have no identifiable thrombotic cause. The interplay of genetic and environmental factors responsible for aPL development and the mechanisms by which these antibodies produce disease in APS patients is the focus of this review.

Spatiotemporal expression of the serine protease inhibitor, SERPINE2, in the mouse placenta and uterus during the estrous cycle, pregnancy, and lactation

BACKGROUND

SERPINE2, also known as glia-derived nexin or protease nexin-1, belongs to the serine protease inhibitor (SERPIN) superfamily. It is one of the potent serpins that modulates the activity of the plasminogen activator (PA) and was implicated in tissue remodeling. In this study, we investigated the expression patterns of SERPINE2 in the mouse placenta and uterus during the estrous cycle, pregnancy, and lactation.

METHODS

SERPINE2 was purified from mouse seminal vesicle secretion using liquid chromatography (LC) and identified by LC/tandem mass spectrometry. The antiserum against the SERPINE2 protein was raised in rabbits. To reveal the uterine and placental expression of SERPINE2, tissues at various stages were collected for real-time PCR quantification, Western blotting, and immunohistochemical staining.

RESULTS

Serpine2 mRNA was the major PA inhibitor in the placenta and uterus during the estrous cycle, pregnancy, and lactation, although Serpine1 mRNA had higher expression levels than Serpine2 mRNA in the placenta. Plat seemed to be the major PA in the mouse uterus and placenta. Antiserum against the SERPINE2 protein specifically recognized two forms of SERPINE2 and an extra 75-kDa protein, which was probably a complex of SERPINE2 with a certain protease, from among thousands of protein components in the tissue extract as demonstrated by Western blotting. In the uterus, SERPINE2 was primarily localized in luminal and glandular epithelial cells but it also was detected in circular and longitudinal smooth muscle cells during the estrous cycle and lactation. It was prominently expressed in decidual stroma cells, the metrial gland, and endometrial epithelium of the pregnant uterus. In the placenta, SERPINE2 was expressed in trophoblasts of the labyrinth and spongiotrophoblasts. However, its expression was remarkably reduced in giant cells which existed in the giant cell-decidual junction zone. In contrast, prominent expression of SERPINE2 seemed to be detected on clusters of glycogen cells near the junction zone. In addition, yolk sac membranes also showed high expression of SERPINE2.

CONCLUSIONS

These findings indicate that SERPINE2 is a major PA inhibitor in the placenta and uterus during the estrous cycle, pregnancy, and lactation. It may participate in the PA-modulated tissue remodeling process in the mouse placenta and uterus.

Proteomic analysis of the major cellular proteins of bovine trophectoderm cell lines derived from IVP, parthenogenetic and nuclear transfer embryos: Reduced expression of annexins I and II in nuclear transfer-derived cell lines

Trophectoderm cell lines were established from 8-day in vitro-cultured embryos of cattle derived from fertilization (IVF), somatic cell nuclear transfer (NT), or parthenogenetic activation (P) of in vitro-matured oocytes and from five 8-day-old in vivo (V) embryos. The most abundant cellular proteins of 5 V-, 16 NT-, 12 P-, and 16 IVF-derived cell lines were compared by 2D-gel electrophoresis and mass spectrometry; that is, the unaltered thiourea/urea extract of each cell culture was analyzed. Common protein spots (n=118) were examined, and 95% were identified with significant scores from protein and gene database searches. Of the proteins detected and identified, actin and cytokeratin-8 were found to be the most abundant. Other prominent cellular proteins were metabolic enzymes such as aldose reductase, phosphoglycerate mutase, enolase, triosephosphate isomerase, cytoskeletal interacting proteins transgelin and stratifin, anti-oxidant proteins peroxiredoxin 1 and anti-oxidant protein 2, and the calcium-dependent lipid-binding proteins annexins I and II. In comparative analysis of the 2D-gels, the NT-derived trophectoderm had less annexins I and II in comparison to the IVF- and P-derived trophectoderm. Because annexins I and II are abundant in the placenta and have functions important to the maintenance of placentation, the down-regulation of the annexin genes in the cultured NT trophectoderm may be related to the frequent failures of NT pregnancies.

Comparative proteomic and regulatory network analyses of the elongating pig conceptus

Embryo loss during peri-implantation can approach 20% in swine following artificial insemination or natural mating and coincides with rapid conceptus elongation. The objective of the present study was to establish a comprehensive profile of the abundant proteins of the pig conceptus at the time prior to implantation and identify stage-specific changes during elongation. The abundant proteins of a homogenous population of gestational day-11 ovoid (0.7-1 cm) and gestational day-12 filamentous (15-20 cm) porcine concepti were compared by extracting proteins from three independent conceptus pools and separating the proteins by 2-DE. Proteins in 305 spots were analyzed by MALDI-TOF or additionally by LC-MS/MS and 275 were positively identified representing 174 distinct proteins. The proteins could be classified into the following functional categories: cell proliferation/differentiation, cytoskeleton, metabolism, and stress response. Based on spot density, 35 proteins associated with cell proliferation, differentiation, apoptosis, and embryo/maternal signaling, were found to be differentially expressed between ovoid and filamentous concepti. A comparison of the protein expression profile with transcriptomic data from pig concepti of the same developmental stages identified similarities and dissimilarities between protein and mRNA expression profiles. This proteomic study helps to elucidate the biological mechanisms underlying the early embryonic development of the pig.

Retinoids regulate human amniotic tissue-type plasminogen activator gene by a two-step mechanism

The collagenolytic effects of the tissue-type plasminogen activator (t-PA) leading to extracellular matrix degradation are clearly involved in the physiopathology of human foetal membranes rupture. Nevertheless, the regulation of t-PA gene expression in extraembryonic developmental contexts remains unknown. The aim of our study is to propose the retinoic acids (RAs) as molecular regulators of t-PA expression in foetal membranes. RA induced t-PA mRNA and proteins in a time-dependent manner in amniotic membrane explants and Wistar Institute Susan Hayflick (WISH) cells. Furthermore, the use of cycloheximide revealed a two-step regulation of t-PA gene. Gene reporter assays confirmed that the RA-induced t-PA gene expression occurred through interactions of retinoid receptors (RARs and RXRs) with a DR5 response element located at –7 kb from the transcription site. Site-directed mutagenesis of this region of the t-PA promoter showed that SP1 factor was also retinoid-mediated induction, and immunoprecipitation assays revealed that SP1 and RAR/RXR interacted physically. Chromatin immunoprecipitation demonstrated that interactions between RARs, RXRs and t-PA promoter were time dependent: RAR-α/RXR-α bound DR5 motif before and up to 12 hrs of RA exposure, and RAR-β/RXR-α bound DR5 response element after 12 hrs of RA treatment. Finally, experiments using shRNA and RAR-β-specific antagonist revealed that reducing RAR-β induction decreased t-PA induction. Altogether, our results established that the RA-mediated regulation of t-PA in human foetal membranes occurred through two steps, with a major role played by RAR-β.

Preterm birth in Caucasians is associated with coagulation and inflammation pathway gene variants

Spontaneous preterm birth (<37 weeks gestation—PTB) occurs in ∼12% of pregnancies in the United States, and is the largest contributor to neonatal morbidity and mortality. PTB is a complex disease, potentially induced by several etiologic factors from multiple pathophysiologic pathways. To dissect the genetic risk factors of PTB a large-scale high-throughput candidate gene association study was performed examining 1536 SNP in 130 candidate genes from hypothesized PTB pathways. Maternal and fetal DNA from 370 US Caucasian birth-events (172 cases and 198 controls) was examined. Single locus, haplotype, and multi-locus association analyses were performed separately on maternal and fetal data. For maternal data the strongest associations were found in genes in the complement-coagulation pathway related to decidual hemorrhage in PTB. In this pathway 3 of 6 genes examined had SNPs significantly associated with PTB. These include factor V (FV) that was previously associated with PTB, factor VII (FVII), and tissue plasminogen activator (tPA). The single strongest effect was observed in tPA marker rs879293 with a significant allelic (p = 2.30×10⁻³) and genotypic association (p = 2.0×10⁻⁶) with PTB. The odds ratio (OR) for this SNP was 2.80 [CI 1.77–4.44] for a recessive model. Given that 6 of 8 markers in tPA were statistically significant, sliding window haplotype analyses were performed and revealed an associating 4 marker haplotype in tPA (p = 6.00×10⁻³). The single strongest effect in fetal DNA was observed in the inflammatory pathway at rs17121510 in the interleukin-10 receptor antagonist (IL-10RA) gene for allele (p = 0.01) and genotype (p = 3.34×10⁻⁴). The OR for the IL-10RA genotypic additive model was 1.92 [CI 1.15–3.19] (p = 2.00×10⁻³). Finally, exploratory multi-locus analyses in the complement and coagulation pathway were performed and revealed a potentially significant interaction between a marker in FV (rs2187952) and FVII (rs3211719) (p<0.001). These results support a role for genes in both the coagulation and inflammation pathways, and potentially different maternal and fetal genetic risks for PTB.

EGF increases expression and activity of PAs in preimplantation rat embryos and their implantation rate

BACKGROUND

Embryo implantation plays a major role in embryogenesis and the outcome of pregnancy. Plasminogen activators (PAs) have been implicated in mammalian fertilization, early stages of development and embryo implantation. As in-vitro developing embryos resulted in lower implantation rate than those developed in-vivo we assume that a reduced PAs activity may be involved. In the present work we studied the effect of EGF on PAs activity, quantity and embryo implantation.

METHODS

Zygotes were flushed from rat oviducts on day one of pregnancy and grown in-vitro in R1ECM supplemented with EGF (10 ng/ml) and were grown up to the blastocyst stage. The control groups were grown in the same medium without EGF. The distribution and quantity of the PAs were examined using fluorescence immunohistochemistry followed by measurement of PAs activity using the chromogenic assay. Implantation rate was studied using the embryo donation model.

RESULTS

PAs distribution in the embryos was the same in EGF treated and untreated embryos. Both PAs were localized in the blastocysts' trophectoderm, supporting the assumption that PAs play a role in the implantation process in rats.EGF increased the quantity of uPA at all stages studied but the 8-cell stage as compared with controls. The tissue type PA (tPA) content was unaffected except the 8-cell stage, which was increased. The activity of uPA increased gradually towards the blastocyst stage and more so due to the presence of EGF. The activity of tPA did not vary with the advancing developmental stages although it was also increased by EGF. The presence of EGF during the preimplantation development doubled the rate of implantation of the treated group as compared with controls.

Expression and purification of recombinant human annexin A2 in Pichia pastoris and utility of expression product for detecting annexin A2 antibody

Annexin A2, a Ca2+-dependent phospholipid binding protein, is abundantly expressed in various human organs, which exists as either a membrane-associated, cytosolic or soluble form in serum. We constructed expression systems for recombinant human annexin A2 (rhA2) using Pichia pastoris. The systems are designed to secrete rhA2 as either the N- or C-terminally His6-tagged form to facilitate purification. Both types of rhA2 were overexpressed, but in the N-terminal-truncated form as revealed from the results of N-terminal amino acid sequencing and Western blotting. Therefore, further purification of N-terminally His6-tagged rhA2 was not feasible because of the removal of the N-terminal His6-tag sequence. C-terminally His6-tagged rhA2 was expressed as either a glycosylated or a nonglycosylated form, and the nonglycosylated form was purified using the combination of nickel-immobilized affinity, concanavalin A and cation exchanged column chromatographies. The solid-phase binding of rhA2 was examined by enzyme-linked immunosorbent assay (ELISA), which revealed the specific reactivity of rhA2 against an anti-annexin A2 monoclonal antibody. These results suggest that the expression system using P. pastoris is useful for the preparation of rhA2 that is applicable to the ELISA detection of the anti-annexin A2 antibody.

PGF2alpha induced differential expression of genes involved in turnover of extracellular matrix in rat decidual cells

In the rat, the decidual tissue is an important component for maternal recognition of pregnancy. Decidualization can be induced by either the implantation of the blastocyst or by artificial stimuli. The process of decidua formation or decidualization, is characterized by growth and differentiation of endometrial stromal cells. Prostaglandin F2alpha (PGF2alpha) has been shown to be involved in inhibition of implantation, alteration of embryo development, induction of luteal regression, and the mediation of pregnancy loss induced by microorganism infections. In order to establish a direct role for PGF2alpha in decidual function, we have evaluated its effects on the expression of an extensive array of genes using primary decidual cell culture. Upon treatment with PGF2alpha sixty genes were significantly down-regulated whereas only six genes were up-regulated (from a total of 1176 genes studied). Interestingly, the majority of the genes inhibited by PGF2alpha are either directly or indirectly involved in the turnover of the extracellular matrix (ECM). Genes such as gelatinase A (MMP2), cathepsin L, tissue inhibitor metalloproteinases 2 (TIMP2) and 3 (TIMP3), plasminogen activator inhibitor1 (PAI1), tissue type plasminogen activator (tPA), urokinase plasminogen activator (tPA), endothelin 1, calponin, carboxypeptidase D and calponin acidic were down regulated. The opposite effect was observed for prostromelysin 53 kDa (proMMP3), plasma proteinase I alpha and alpha 1 antiproteinase, all of which were significantly up-regulated by PGF2alpha. The results strongly suggest that the abortificient role of elevated levels of PGF2alpha after implantation is due, in large part, to inhibition of genes involved in the normal turnover of the extracellular matrix necessary for decidual formation.

Differences in the implantation rates of rat embryos developed in vivo and in vitro: possible role for plasminogen activators

OBJECTIVE

To assess the participation of urokinase-type (uPA) and tissue-type (tPA) plasminogen activators in embryo development and implantation.

DESIGN

The study was set to compare the activities of PAs in embryos developed in vivo and in vitro and their implantation rates. Endometrial PA activity was studied as well.

SETTING

University laboratories.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Plasminogen activator activity in embryos.

RESULT(S)

Whereas tPA activity in in vivo-developed embryos decreased from the zygote to the blastocyst stages, it did not change in embryos developed in vitro. The activity of uPA was lowest in two-cell-stage embryos, both in vivo and in vitro, and increased as embryos developed into blastocysts. The activity of uPA in the in vitro-developed embroys was lower in all developmental stages as compared with those developed in vivo. Whereas endometrial tPA activity did not change during the preimplantation period, uPA activity increased gradually toward the time of implantation. The implantation rate of the in vitro-developed embryos was much lower than that of those developed in vivo.

CONCLUSION(S)

Taken together, these data indicate that in vitro embryo development leads to lower PA activities as compared with in vivo development. The increased activity of uPA toward the blastocyst stage supports uPA's role in the implantation process. Moreover, the rise in endometrial uPA might also indicate its importance in this process.

Levels of plasminogen activators and their inhibitors in maternal and umbilical cord plasma in severe preeclampsia

OBJECTIVE

The purpose of this study was to evaluate the plasminogen activator system in maternal and umbilical cord plasma in patients with severe preeclampsia compared with control subjects with normotensive pregnancies.

STUDY DESIGN

Maternal blood was sampled from 42 patients at a median gestational age of 32 weeks; after delivery, arterial and venous umbilical cord blood was sampled from 37 and 36 of these patients, respectively. Maternal blood from women with uncomplicated pregnancies was sampled at the gestational age of 32 weeks (n = 18, group I), and umbilical cord blood was sampled after premature deliveries of normotensive pregnancies (n = 5, group II). Data were analyzed with the use of Mann-Whitney U tests.

RESULTS

Patients had significantly higher tissue plasminogen activator (P <.01) and unchanged urokinase plasminogen activator plasma levels compared with control subjects at 32 weeks of gestation; lower plasminogen activator inhibitor type 2 (P < 0.01) and no different plasminogen activator inhibitor type 1 concentrations were observed compared to control subjects at 32 weeks of gestation. In the arterial and venous umbilical cord plasma of patients, plasminogen activator inhibitor type 1 levels were significantly higher(P <.01) compared with control subjects at 32 weeks of gestation, although urokinase plasminogen activator levels in arterial and venous umbilical cord plasma (P < 0.01) were significantly lower.

CONCLUSION

Lower plasminogen activator inhibitor type 2 levels are associated with placental insufficiency, and higher tissue plasminogen activator levels are associated with endothelial dysfunction in patients with severe preeclampsia. The higher plasminogen activator inhibitor type 1 levels and lower urokinase plasminogen activator levels in umbilical cord of these patients are suggestive of decreased fibrinolysis in the fetal circulation.